A door at an escalator handrail entry is known from German Pat. No. 20 54 640, the content of which is hereby incorporated by reference. The U.S. counterpart of this German Patent is U.S. Pat. No. 3,809,206. It secures the entry of the handrail of an escalator against the danger of dragging in objects, particularly the hands of playing children. If a child grabs the handrail but does not le go in time, then the fingers together with the handrail move against the door, namely against its rear wings which open elastically by forcing away a slider by acting against inclined cam surfaces or ramps. Thereby the front door wings are unlocked also and offer a large opening into which all of the arm can extend without injury until the escalator, turned OFF as the door wings are opened, comes to a stop. The most important requirements of this design therefore are that the door shall open even upon weak contact and shall reliably shut off the escalator. Essentially this means that the slider carrying out this function must operate reliably.
Unfortunately, in this known design, such reliability is not unfailing. The slider rests against springs in the direction of push at both its ends and is guided by guide rods. This kind of slider guidance may appear appropriate at first thought, the more so because the slider is very wide and thereby is secured against rotation. It has been found, however, that this kind of slider guidance also entails a risk of jamming that might inhibit the design function and might lead to injury, especially to the arms of children.